NAME

SYNOPSIS

DESCRIPTION

The toupper() function converts a lower-case letter to the corresponding
upper-case letter. The _toupper() function is identical to toupper() ex-
cept that c must be a lower-case letter.

RETURN VALUES

If the argument to the toupper() function is a lower-case letter, the
corresponding upper-case letter is returned if there is one; otherwise
the argument is returned unchanged. If the argument to the _toupper()
function is a lower-case letter, the corresponding upper-case letter is
returned; otherwise the output is undefined.